ES6 symbols: refine test for getOwnPropertyNames

test/mjsunit/harmony/symbols.js

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 166 matching lines @@
 }
 
 
 function TestKeyEnum(obj) {
   for (var name in obj) {
     assertFalse(%_IsSymbol(name))
   }
 }
 
 
-function TestKeyKeys(obj) {
+function TestKeyNames(obj) {
   assertEquals(0, Object.keys(obj).length)
-  assertTrue(symbols.length <= Object.getOwnPropertyNames(obj).length)
+
+  var names = Object.getOwnPropertyNames(obj)
+  assertTrue(symbols.length <= names.length)
+  // TODO(rossberg): once we have iterators, the following would be:
+  //   var expected = new Set(symbols)
+  var expected = new Set
+  for (var i = 0; i < symbols.length; ++i) expected.add(symbols[i])
+  for (var i = 0; i < names.length; ++i) {
+    var name = names[i]
+    var asString = String(name)
+    if (asString !== name) {
+      assertEquals("[object Symbol]", asString)
+      assertTrue(expected.has(name))
+      expected.delete(name)
+    }
+  }
+  assertEquals(0, expected.size)
 }
 
 
 function TestKeyDescriptor(obj) {
   for (var i in symbols) {
     var desc = Object.getOwnPropertyDescriptor(obj, symbols[i]);
     assertEquals(i|0, desc.value)
     assertTrue(desc.configurable)
     assertEquals(i % 2 == 0, desc.writable)
     assertEquals(i % 2 == 0, desc.enumerable)
@@ skipping 15 matching lines @@
 
 var objs = [{}, [], Object.create(null), Object(1), new Map, function(){}]
 
 for (var i in objs) {
   var obj = objs[i]
   TestKeySet(obj)
   TestKeyDefine(obj)
   TestKeyGet(obj)
   TestKeyHas(obj)
   TestKeyEnum(obj)
-  TestKeyKeys(obj)
+  TestKeyNames(obj)
   TestKeyDescriptor(obj)
   TestKeyDelete(obj)
 }